Catalyst for a catalytic ink and uses thereof

ABSTRACT

A catalyst for a catalytic ink includes a support particle and a metallic material supported on the support particle. The metallic material is diamminesilver hydroxide, a silver salt, a palladium salt, a gold salt, chloroauric acid, or combinations thereof. A catalytic ink obtained from the catalyst and use of the same to fabricate a conductive circuit are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Divisional of U.S. patent application Ser. No.15/088,746 filed Apr. 1, 2016, which claims priority of Taiwanese PatentApplication No. 104110917, filed on Apr. 2, 2015, which are incorporatedby reference as if fully set forth.

FIELD

Embodiments of the present disclosure generally relate to a catalyst,and more particularly to a catalyst for a catalytic ink and usesthereof.

BACKGROUND

With technology advances, various electronic products are widely usednowadays. Conductive circuits are important elements for the electronicproducts, and hence a method for fabricating conductive circuits of theelectronic products is continuously being developed and improved.

In recent years, the application of ink printing techniques tomanufacture a conductive circuit has caught much attention. CN 1946880 Bdiscloses a method of providing a pattern of a metal on a non-conductivesubstrate by virtue of ink printing techniques. The method includes thesteps of applying a catalytic ink having a source of catalytic metalions (such as palladium ions and gold ions) in a desired pattern on asurface of the non-conductive substrate; reducing the source ofcatalytic metal ions to its associated metal with a suitable reducingagent; depositing an electroless metal layer on the pattern of catalyticink; and plating an electrolytic metal on the electroless metal layer toproduce the desired pattern of metal on the substrate.

CN 101640979 A discloses another method of manufacturing a conductivecircuit using ink printing techniques. The method disclosed thereinincludes the steps of printing a catalytic ink containing silver saltsolution (such as a silver nitrate solution, a silver sulfate solution,and a silver acetate solution) to form a circuit pattern on a substrate;irradiating the circuit pattern to reduce silver ions contained in thesilver salt solution to silver metals, thereby forming a circuitprecursor; and plating a conductive metal layer on the circuit precursorto obtain the conductive circuit.

However, the metal ions (such as palladium, silver and gold ions, etc.)in the solution (i.e., in the liquid state) are usually unstable, andtend to undergo undesired reactions. Moreover, if the metal ions are ina non-liquid state or exposed to high temperatures, the reactivitythereof would be greatly reduced. Given this, the metal ions included inthe catalytic ink as disclosed in the aforesaid prior art, when appliedonto the substrate, must be immediately reduced into a catalytic metalin order to avoid occurrence of the aforesaid undesired reaction orreduced reactivity of the metal ions.

Therefore, the applicants have endeavored to develop a catalystincluding catalytic metal ions that are stable and do not requireconducting of a reduction reaction immediately when applied onto asubstrate.

SUMMARY

Therefore, an object of the disclosure is to provide a catalyst for acatalytic ink that may alleviate at least one of the drawbacks of theprior art.

According to the disclosure, the catalyst includes a support particleand a metallic material supported on the support particle. The metallicmaterial may be selected from the group consisting of diamminesilverhydroxide, a silver salt, a palladium salt, a gold salt, chloroauricacid, and combinations thereof.

A second object of the present disclosure is to provide a catalytic inkincluding the aforesaid catalyst, a resin and a solvent.

A third object of the present disclosure is to provide a method formanufacturing the aforesaid catalytic ink. According to the disclosure,the method may include the steps of: mixing the support particle and asolution of the metallic material to form the catalyst; and mixing thecatalyst, the resin and the solvent.

A fourth object of the present disclosure is to provide a method forfabricating a conductive circuit. According to the disclosure, themethod may include the steps of: printing the aforesaid catalytic ink ona substrate to form an ink layer on the substrate; subjecting themetallic material of the catalyst to a reduction reaction so as to forma catalytic metal; and contacting the catalytic metal of the ink layerwith a solution containing conductive metal ions, such that a conductivemetal is formed and deposited on the ink layer by reduction of theconductive metal ions using the catalytic metal.

A fifth object of the disclosure is to provide another method forfabricating a conductive circuit. According to the disclosure, themethod may include the steps of: forming an ink layer on a substrate,the ink layer including a core-shell type catalyst having a core and ashell layer surrounding the core, the shell layer including a metallicmaterial; subjecting the metallic material of the shell to a reductionreaction so as to form a catalytic metal; contacting the catalytic metalof the ink layer with a solution containing conductive metal ions, suchthat a conductive metal is formed and deposited on the ink layer byreduction of the metallic material using the catalytic metal.

DETAILED DESCRIPTION

An embodiment of a catalyst of this disclosure includes a supportparticle and a metallic material supported on the support particle. Incertain embodiments, the catalyst includes a plurality of the supportparticles on each of which the metallic material is supported. Themetallic material may be diamminesilver hydroxide, a silver salt, apalladium salt, a gold salt, chloroauric acid, or combinations thereof.

The silver salt may be silver nitrate, silver carbonate, silver sulfate,or combinations thereof. The palladium salt may be palladium chloride,palladium acetate, or the combination thereof. In certain embodiments,the metallic material is diamminesilver hydroxide.

In certain embodiments, the metallic material includes catalytic ionssupported on the support particle. The catalytic ions may be silvercomplex ions, silver ions, palladium complex ions, palladium ions, goldcomplex ions, or combinations thereof.

In certain embodiments, the catalytic ions may be diamminesilver complexions, Ag⁺, [AgCN₂]²⁻, [AgCO₂]⁺, [AgS₂O₃]³⁻, PdCl₄ ²⁻, Pd²⁺, [Au(CN)₂]⁻,AuCl₄ ⁻, or combinations thereof.

In certain embodiments, the support particle has a diameter not greaterthan 250 nm. When the support particle has a diameter greater than 250nm, in a given volume of the catalyst which is composed of a pluralityof the support particles, the total surface area of the supportparticles would be smaller than that having the diameter less than 250nm. In other words, the surface area of the support particles to beattached by the metallic material would be reduced. When the catalyst iscomposed of a plurality of the support particles having a diameter lessthan 220 nm, the support particles are likely to be aggregated togetherand are difficult to be well dispersed. Therefore, in certainembodiments, the diameter of the support particle ranges from 220 nm to250 nm.

In certain embodiments, the support particle may be a titanium dioxideparticle, a zinc oxide particle, an aluminum oxide particle, acerium(IV) oxide particle, a lanthanum oxide particle, a barium sulfateparticle, a magnesium silicate particle, a carbon particle, orcombinations thereof. In certain embodiments, the support particle is atitanium dioxide particle.

In certain embodiments, the catalyst may have a core-shell structure andinclude a core and a shell layer. The core includes the supportparticle, and the shell layer includes the metallic material.

Since the metallic material is supported on the support particle, themetallic material is relatively stable. In other words, the catalyticmetal ions of the metallic material would not undergo an undesiredreaction and would not be adversely affected in terms of the catalyticactivity.

The disclosure also provides a catalytic ink including the aforesaidcatalyst, a resin and a solvent. The resin suitable for use in thisdisclosure may be a polyurethane resin, an aldehyde resin, a ketoneresin, a phenol-formaldehyde resin, an epoxy resin, a silicone resin, amelamine resin, a fatty acid resin, an acrylic resin, or combinationsthereof. In certain embodiments, the resin may be the polyurethaneresin, the silicone resin, the epoxy resin, the melamine resin, orcombinations thereof.

In certain embodiments, the resin in the catalytic ink is in an amountranging from 1 to 3 parts by weight based on 1 part by weight of thecatalyst. In certain embodiments, the resin is in an amount ranging from1.2 to 2.6 parts by weight based on 1 part by weight of the catalyst.

The solvent suitable for use in this disclosure may be ketone, alcohol,ester, ether, benzene, mineral spirit, or combinations thereof.

Examples of the ketone suitable for use in this disclosure may includecyclohexanone, isophorone, acetone, butanone, N-methyl-2-pyrrolidone,and combinations thereof.

Examples of the alcohol suitable for use in this disclosure may includeisopropanol, n-butanol and the combination thereof.

Examples of the ester suitable for use in this disclosure may includeethyl acetate, n-butyl acetate, ethylene glycol monoethyl ether acetate,and combinations thereof.

Examples of the ether suitable for use in this disclosure may includedipropylene glycol methyl ether, ethylene glycol monobutyl ether and thecombination thereof.

In certain embodiments, the solvent is N-methyl-2-pyrrolidone orethylene glycol monobutyl ether.

In certain embodiments, the solvent in the catalytic ink is in an amountranging from 0.5 to 3 parts by weight based on 1 part by weight of thecatalyst. In certain embodiments, the solvent is in an amount rangingfrom 0.7 to 2.6 parts by weight based on 1 part by weight of thecatalyst.

The catalytic ink of the present disclosure may further include anadditive. The additive may be a curing agent, a silane coupling agent, alubricant such as castor oil, a smoothing agent, a dispersing agent, adefoaming agent, a leveling agent, a wetting agent, an anti-blockingagent, or combinations thereof.

In certain embodiments, the additive may be the curing agent, the silanecoupling agent or the combination thereof. In certain embodiments, thecuring agent in the catalytic ink is in an amount ranging from 0.1 to0.23 parts by weight based on 1 part by weight of the catalyst. Incertain embodiments, the silicone coupling agent in the catalytic ink isin an amount ranging from 0.02 to 0.04 parts by weight based on 1 partby weight of the catalyst.

Examples of the curing agent suitable for use in this disclosure mayinclude methyl benzoate, isocyanate and the combination thereof. Incertain embodiments, the curing agent is isocyanate, and the silanecoupling agent is aminosilane coupling agent.

This disclosure also provides a method for manufacturing the aforesaidcatalytic ink. An embodiment of the method includes the steps of: mixingthe support particle and a solution of the metallic material to form thecatalyst; and mixing the catalyst, the resin and the solvent.

In certain embodiments, the solution of the metallic material has aconcentration ranging from 0.1 N to 0.5 N.

In certain embodiments, the aforesaid additive may be added during thestep of mixing the catalyst, the resin and the solvent.

This disclosure further provides a method for fabricating a conductivecircuit. An embodiment of the method includes the steps of: printing theaforesaid catalytic ink on a substrate so as to form an ink layer on thesubstrate; subjecting the metallic material of the catalyst to areduction reaction so as to reduce the catalytic ions of the metallicmaterial into a catalytic metal; and contacting the catalytic metal ofthe ink layer with a solution containing conductive metal ions, suchthat a conductive metal is formed and deposited on the ink layer byreduction of the conductive metal ions using the catalytic metal.

According to the disclosure, since the catalytic ions of the metallicmaterial are supported on the support particle, the metallic materialhas good stability and is unlikely to undergo undesired non-reductionreactions. The ink layer formed therefrom can be preserved for a longtime after being applied on the substrate, and the metallic materialincluded in the ink layer does not require immediate conducting of areduction reaction. In certain embodiments, the catalytic ions of themetallic material included in the ink layer on a substrate couldmaintain its ionic form and reactivity for about one month.

The substrate suitable for use in this disclosure may be made from amaterial e.g., polycarbonate, polyethylene terephthalate, polyamide,poly(methyl methacrylate), an epoxy resin, syndiotactic polystyrene,polyphenylene sulfide, glass, ceramics, acrylonitrile-butadiene-styrenecopolymer, and combinations thereof.

In certain embodiments, the step of subjecting the metallic material ofthe catalyst to the reduction reaction is conducted using a reducingagent. In certain embodiments, the reducing agent is formaldehyde.

In certain embodiments, when the metallic material of the catalyst isdiamminesilver hydroxide, the step of subjecting the metallic materialof the catalyst to the reduction reaction may be conducted by UVexposure, i.e., the catalytic ions are reduced into the catalytic metalby UV light. In certain embodiments, the UV has a wavelength rangingfrom 230 nm to 380 nm. In certain embodiments, the wavelength of the UVis 254 nm.

In certain embodiments, the support particle may be a photocatalyst, andthe step of subjecting the metallic material of the catalyst to thereduction reaction includes activating the photocatalyst by UV exposure,and reducing the catalytic ions of the metallic material to a catalyticmetal using the activated photocatalyst. In certain embodiments, thesupport particle is titanium dioxide.

According to the disclosure, the conductive metal ions may be copperions, nickel ions or the combination thereof.

In certain embodiments, the method for fabricating the conductivecircuit of the disclosure may further include a step of patterning theconductive metal formed on the ink layer so as to form the conductivecircuit. The step may be performed by wet-etching techniques or laserablation, but is not limited thereto.

The disclosure will be further described by way of the followingexamples. However, it should be understood that the following examplesare solely intended for the purpose of illustration and should not beconstrued as limiting the disclosure in practice.

EXAMPLES

The sources of the chemicals used in the following examples are listedin Table 1.

TABLE 1 Chemical Source Support particle titanium dioxide 1 Metallicmaterial silver nitrate (aq) 2 (diamminesilver ammonia (aq) 1 hydroxide)Resin polyurethane resin 1 silicone resin 1 epoxy resin 3 melamine resin4 Solvent N-methyl-2-pyrrolidone 1 ethylene glycol monobutyl ether 1Curing agent isocyanate 1 Coupling agent aminosilane coupling agent 1Conductive metal Copper plating solution 5 ion solution 1: Jia WangChemical Industry Co. 2: Camco Enterprises Co., Ltd. 3: Ezbond ChemicalCo., Ltd. 4: An Fong Development Co., Ltd. 5: MacDermid Chemical TaiwanLtd.

Preparation of a Catalyst Preparative Example 1

0.1 N aqueous solution of silver nitrate was added to 25 wt % of aqueousammonia. When the resulting solution became clear, a solution ofdiamminesilver hydroxide (0.1 N) was obtained.

The titanium dioxide particles having a diameter of 250 nm and thesolution of diamminesilver hydroxide were mixed at a weight ratio of2.65:1 so as to produce a catalyst. The resultant catalyst has acore-shell structure, and includes a core of titanium dioxide and ashell layer of diamminesilver hydroxide.

Preparation of a Catalytic Ink Example 1 (E1)

Polyurethane resin (24 g) and the catalyst of Preparative Example 1(25.8 g) were placed in an agitator (Shin Kwang Machinery Industry Co.,Ltd.; Model No. G-100R) and stirred at 800 rpm for 300 seconds so as toobtain a first mixture.

Silicone resin (19.5 g), epoxy resin (9 g) and N-methyl-2-pyrrolidone(2.8 g) were sequentially added to the first mixture at an agitationspeed of 800 rpm for 300 seconds so as to obtain a second mixture.

Isocyanate (3 g) was added to the second mixture and then stirred at 800rpm for 60 seconds so as to obtain a third mixture.

N-methyl-2-pyrrolidone (21.2 g) was added to the third mixture in theagitator and then stirred at 300 rpm for 20 minutes with the agitatorbeing covered so as to obtain the catalytic ink.

Example 2 (E2)

Polyurethane resin (24 g) and the catalyst of Preparative Example 1 (16g) were placed in an agitator and stirred at 800 rpm for 300 seconds soas to obtain a first mixture.

Melamine resin (0.4 g) and ethylene glycol monobutyl ether (8 g) weresequentially added to the first mixture at an agitation speed of 800 rpmfor 300 seconds so as to obtain a second mixture.

Isocyanate (3.6 g) was added to the second mixture and then stirred at800 rpm for 60 seconds so as to obtain a third mixture.

Ethylene glycol monobutyl ether (32 g) was added to the third mixture inthe agitator and then stirred at 300 rpm for 20 minutes with theagitator being covered so as to obtain the catalytic ink.

Example 3 (E3)

Polyurethane resin (19.2 g) and the catalyst of Preparative Example 1(17.1 g) were placed in an agitator and stirred at 800 rpm for 300seconds so as to obtain a first mixture.

Isocyanate (3 g) was added to the first mixture at an agitation speed of800 rpm for 60 seconds so as to obtain a second mixture.

Silicone resin (3 g) was added to the second mixture and then stirred at800 rpm for 300 seconds so as to obtain a third mixture.

Ethylene glycol monobutyl ether (19.2 g) was added to the third mixturein the agitator and then stirred at 300 rpm for 20 minutes with theagitator being covered so as to obtain the catalytic ink.

Example 4 (E4)

Polyurethane resin (30 g) and the catalyst of Preparative Example 1(13.5 g) were placed in an agitator and stirred at 800 rpm for 300seconds so as to obtain a first mixture.

Melamine resin (1 g), silicone resin (3 g) and epoxy resin (1 g) weresequentially added to the first mixture at an agitation speed of 800 rpmfor 300 seconds so as to obtain a second mixture.

Isocyanate (2.25 g) was added to the second mixture and then stirred at800 rpm for 60 seconds so as to obtain a third mixture.

An aminosilane coupling agent was added to the third mixture and thenstirred at 800 rpm for 300 seconds so as to obtain a fourth mixture.

Ethylene glycol monobutyl ether (10 g) was added to the fourth mixturein the agitator and then stirred at 300 rpm for 20 minutes with theagitator being covered so as to obtain the catalyst.

Each component and the content thereof (based on 1 part by weight of thecatalyst) used in the preparation of the catalytic inks of Examples 1-4are respectively summarized in Table 2.

TABLE 2 Content (part by weight) Component E1 E2 E3 E4 Resinpolyurethane resin 0.930 1.500 1.123 2.222 silicone resin 0.756 — 0.1750.222 epoxy resin 0.349 — — 0.074 melamine resin — 0.025 — 0.074 SolventN-methyl-2-pyrrolidone 0.930 — — — Ethylene glycol — 2.500 1.123 0.740monobutyl ether Curing agent isocyanate 0.116 0.225 0.175 0.167 Couplingagent aminosilane coupling — — — 0.033 agent

Preparation of a conductive circuit Application Examples 1-4 (AE1-4)

The conductive circuits of Application Examples 1-4 were prepared by amethod as described below and respectively using the catalytic inks ofExamples 1-4. The substrates used in AE1 to AE4 are listed in Table 3.

TABLE 3 Substrate AE1 polyethylene terephthalate substrate AE2poly(methyl methacrylate) substrate AE3 glass substrate AE4 epoxy resinsubstrate

The catalytic ink of each of Examples 1-4 was printed onto the substrateto form an ink layer thereon. It should be noted that since the metallicmaterial of the catalyst included in the ink layer is relatively stableand does not tend to undergo undesired reactions, the ink layer formedon the substrate can be preserved for a long time, and does not need thefollowing step to be conducted immediately. The ink layer of AE1 to AE4can be preserved for one month.

The ink layer on the substrate was irradiated by deuterium lamp with awavelength of 254 nm for 5 to 8 minutes so as to activate the titaniumdioxide particles. The activated titanium dioxide particles which serveas the photocatalyst are capable of reducing the diamminesilverhydroxide of the catalyst to form silver metals (i.e., catalyticmetals).

The resulting ink layer as well as the substrate was immersed in acopper plating solution having the components as shown in Table 4 for 15minutes, such that a layer of copper metals (conductive metals) wasformed and deposited on the ink layer by reduction of the cooper ionsusing the silver metals. It is noted that the time for immersing the inklayer in the copper plating solution may vary depending on the desiredthickness of the layer of copper metal to be formed on the substrate.

TABLE 4 Component Content (g/L) Formaldehyde 2.2 Sodium hydroxide 4.2Copper ion 2 Ethylenediaminetetraacetic acid 0.13 (EDTA)

The layer of copper metal was then etched by 3-Axis fiber laser (KEYENCETaiwan Co., Ltd.; Model No. MD-5100) with a wavelength of 1090 nm toremove an unwanted portion of copper metal so as to form the conductivecircuit.

In summary, by supporting the metallic material on the support particle,the catalytic ions of the metallic material become stable. Thus, thecatalytic ink made therefrom can be preserved for a long time whenprinting on the substrate and does not require a reduction reaction tobe conducted immediately to transform catalytic ions into the catalyticmetals.

In the description above, for the purposes of explanation, numerousspecific details have been set forth in order to provide a thoroughunderstanding of the embodiment(s). It will be apparent, however, to oneskilled in the art, that one or more other embodiments may be practicedwithout some of these specific details. It should also be appreciatedthat reference throughout this specification to “one embodiment,” “anembodiment,” an embodiment with an indication of an ordinal number andso forth means that a particular feature, structure, or characteristicmay be included in the practice of the disclosure. It should be furtherappreciated that in the description, various features are sometimesgrouped together in a single embodiment, figure, or description thereoffor the purpose of streamlining the disclosure and aiding in theunderstanding of various inventive aspects.

While the disclosure has been described in connection with what is (are)considered the exemplary embodiment(s), it is understood that thisdisclosure is not limited to the disclosed embodiment(s) but is intendedto cover various arrangements included within the spirit and scope ofthe broadest interpretation so as to encompass all such modificationsand equivalent arrangements.

What is claimed is:
 1. A catalytic ink, comprising: a catalyst having asupport particle and a metallic material supported on said supportparticle, said metallic material being selected from the groupconsisting of diamminesilver hydroxide, a silver salt, a palladium salt,a gold salt, chloroauric acid, and combinations thereof; a resin; and asolvent.
 2. The catalyst ink of claim 1, wherein said catalyst has acore-shell structure and includes a core and a shell layer, said coreincluding said support particle, said shell layer including saidmetallic material.
 3. The catalytic ink of claim 1, wherein said supportparticle is selected from the group consisting of titanium dioxideparticle, zinc oxide particle, aluminum oxide particle, cerium(IV) oxideparticle, lanthanum oxide particle, barium sulfate particle, magnesiumsilicate particle, carbon particle, and combinations thereof.
 4. Thecatalytic ink of claim 1, wherein, based on 1 part by weight of saidcatalyst, said resin is in an amount ranging from 1 to 3 parts byweight, and said solvent is in an amount ranging from 0.5 to 3 parts byweight.
 5. The catalytic ink of claim 1, wherein said solvent isselected from the group consisting of ketone, alcohol, ester, ether,benzene, mineral spirit, and combinations thereof.
 6. A method formanufacturing the catalytic ink of claim 1, comprising the steps of:mixing the support particle and a solution of the metallic material toform the catalyst; and mixing the catalyst, the resin and the solvent.7. The method of claim 6, wherein the support particle is added in anamount ranging from 2 to 3 parts by weight based on 1 part by weight ofthe solution of metallic material.
 8. A method for fabricating aconductive circuit, comprising the steps of: printing the catalytic inkof claim 8 on a substrate so as to form an ink layer on the substrate;subjecting the metallic material of the catalyst to a reduction reactionso as to form a catalytic metal; and contacting the catalytic metal ofthe ink layer with a solution containing conductive metal ions, suchthat a conductive metal is formed and deposited on the ink layer byreduction of the conductive metal ions using the catalytic metal.
 9. Themethod of claim 8, wherein the step of subjecting the metallic materialof the catalyst to the reduction reaction is conducted by UV exposure.10. The method of claim 9, wherein the metallic material isdiamminesilver hydroxide.
 11. A method for fabricating a conductivecircuit, comprising the steps of: forming an ink layer on a substrate,the ink layer including a core-shell type catalyst having a core and ashell layer surrounding the core, the shell layer including a metallicmaterial; subjecting the metallic material of the shell to a reductionreaction so as to form a catalytic metal; and contacting the metallicmaterial of the ink layer with a solution containing conductive metalions, such that a conductive metal is formed and deposited on the inklayer by reduction of the metallic material using the catalytic metal.12. The method of claim 11, wherein the step of subjecting the metallicmaterial of the shell to the reduction reaction is conducted using areducing agent.
 13. The method of claim 11, wherein the core includes aphotocatalyst, and the step of subjecting the metallic material of theshell to the reduction reaction includes activating the photocatalyst ofthe core by UV exposure, and reducing the metallic material to acatalytic metal using the activated photocatalyst.